Removing Dried Modified Latex Thinset from Natural Stone

Thinset mortar modified with latex is a cement-based product with latex added to make it more flexible. It is used for the installation of natural stone and glass tiles, and once dried it forms a hard, durable cement that bonds tiles in place. If you are salvaging natural stone tiles, or have tiles on which mortar has dried prematurely, dried thinset can be challenging to remove. Because natural stone is porous, it pulls the moisture from the thinset, creating a tougher bond. Because this bond cannot be dissolved without also dissolving the stone, you need to grind off the thinset with an angle grinder.

1

Place the wire brush cup onto the angle grinder and tighten it into place. The wire brush can grind down and remove the bulk of the cement, and therefore thinset, from surfaces including tiles.

2

Clamp down one edge of the tile to hold it steady on a table. If possible, clamp an opposite edge from the dried thinset. If not possible, clamp whereever you can get a tight hold; you will turn the tile later.

3

Turn on the angle grinder and move it from the center of the tile out to the edges, letting the wire brush break up and remove the thinset. Make several passes until the thinset is mostly removed. The wire brush cannot remove all of it without damaging the tile, so stop before the thinset becomes flush with the surface of the stone.

4

Remove the wire brush attachment from the angle grinder and swap it for a fine grinding attachment. The fine grinding attachment can remove the last of the thinset. Depending on how far into the pores the thinset has gone, and whether or not you are removing thinset from the face of the tile or the back, you may also need to grind down the surface of the stone slightly as well.

5

Pass the angle grinder from the center of the tile out to the sides until the thinset has been removed. If you are grinding the surface of the stone, and only a small amount of thinset was on it, you may need to grind down the entire surface of the stone to keep it level. Stop between passes with the grinder and run your hand over the stone to make sure it is uniformly smooth and level.

6

Change out the fine grinding attachment for a polishing attachment if you need to repolish the surface of the stone. Rub the angle grinder over the entire stone from center to the sides until it has a uniform luster and surface.

Things You Will Need

Angle grinder

Clamp

Wire brush attachment

Fine grinding attachment

Polishing pad (optional)

Warnings

Work slowly. You can quickly grind down too much of the stone at once. If possible, practice on a piece of stone you will not be needing later.

Wear eye protection to guard against dust and small pieces of thinset debris.

About the Author

Sarabeth Asaff has worked in and has written about the home improvement industry since 1995. She has written numerous articles on art, interior design and home improvements, specializing in kitchen and bathroom design. A member in good standing with the National Kitchen and Bath Association, Asaff has working knowledge of all areas of home design.